Cod sursa(job #905018)

Utilizator dicu_dariaDaria Dicu dicu_daria Data 5 martie 2013 12:54:04
Problema Flux maxim Scor 40
Compilator cpp Status done
Runda Arhiva educationala Marime 1.37 kb
#include <cstring>
#include <utility>
#include <fstream>
#include <queue>
#define oo int(2e9)
#define MAX 1010
#define mp make_pair

using namespace std;

bool viz[MAX];
int x, y, z, i, n, m, flow, last, solFlow, from[MAX], D[MAX], cap[MAX][MAX];
queue <int> Q;

bool BF()
{
    memset(from, 0, sizeof(from));
    Q.push(1);
    from[1] = -1;
    while(!Q.empty())
    {
        x = Q.front();
        Q.pop();
        for(i = 1; i <= n; i++)
        if(cap[x][i] and !from[i])
        {
            from[i] = x;
            Q.push(i);
        }
    }
    return from[n];
}
int main()
{
    ifstream fi("maxflow.in");
    ofstream fo("maxflow.out");
    fi >> n >> m;
    for(i = 1; i <= m; i++)
    {
        fi >> x >> y >> z;
        cap[x][y] = z;
        cap[y][x] = 0;
    }
    while(BF())
    {
        for(last = 1; last <= n; last++)
            if(cap[last][n] and from[last])
            {
                flow = cap[last][n];
                for(i = last; from[i] != -1; i = from[i])
                    flow = min(flow, cap[from[i]][i]);
                cap[last][n] -= flow; cap[n][last] += flow;
                for(i = last; from[i] != -1; i = from[i])
                    cap[from[i]][i] -= flow, cap[i][from[i]] += flow;
                solFlow += flow;
            }
    }
    fo << solFlow << "\n";
    return 0;
}